Polymerization process and catalyst system

ABSTRACT

UTILIZATION OF A CATALYST SYSTEM FORMED BY ADMIXING (A) A COMPOUND OF THE FORMULA RNAIX3-0; (B) A TITANIUM TRICHLORIDE-ALUMINUM TRICHLORIDE COMPLEX OF THE APPROXIMATE FORMULA TICL3-1/3ALCL3; AND (C) A PHOSPHITE HAVING THE FORMULA (R&#39;&#39;O)3P OR A PHOSPHONITE HAVING THE FORMULA (RO)2PR IN THE POLYMERIZATION OF 1-OLEFINS RESULTS IN THE PRODUCTION OF POLYMERS HAVING HIGHER MODULUS AND LOWER XYLENES-SOLUBLE CONTENT. IN THE ABOVE FORMULAS, R IS SELECTED FROM ALKYL, CYCLOALKY, AND ARYL GROUPS, AND COMBINATIONS THEREOF, HAVING FROM 1 TO 12 CARBON ATOMSS R&#39;&#39; IS SELECTED FROM MONO- OR DIHALO-SUBSTITUTED ALKYL, CYCLOALKYL, AND ARYL GROUPS AND COMBINATIONS THEREOF HAVING FROM 1 TO 12 CARBONS ATOMS, AND N IS 1 OR 2.

United States Patent Office 3,558,586 Patented Jan. 26, 1971 3,558,586POLYMERIZATION PROCESS AND CATALYST SYSTEM US. Cl. 260-933 10 ClaimsABSTRACT OF THE DISCLOSURE Utilization of a catalyst system formed byadmixing (a) a compound of the formula R AlX (b) a titaniumtrichloride-aluminum trichloride complex of the approximate formula TiCl/3AlCl and (c) a phosphite having the formula (R'O) P or a phosphonitehaving the formula (RO) PR in the polymerization of l-olefins results inthe production of polymers having higher modulus and lowerxylenes-soluble content. In the above formulas, R is selected fromalkyl, cycloalkyl, and aryl groups, and combinations thereof, havingfrom 1 to 12 carbon atoms, R is selected from monoor dihalo-substitutedalkyl, cycloalkyl, and aryl groups and combinations thereof having from1 to 12 carbon atoms, and n is 1 or 2.

BACKGROUND OF THE INVENTION Polymers of alpha-olefins, particularly ofpropylene, have long been known and numerous procedures have beendisclosed for their production. These polymers are characterized by agreater or lesser degree of stereospecificity; they also vary in degreeof crystallinity. Many of the useful properties of these polymers suchas ultimate tensile, hardness. range of melting temperature, etc.,appear to depend upon the crystallinity of the polymer. Flexuralmodulus, a property readily measurable by standard procedures, providesa reliable and consistent means for characterizing these polymers. Thehigher the crystallinity of a polymer, the higher the flexural modulusvalues are found to be. For a commercially attractive product, flexuralmodulus values must be high, preferably above 190,- 000 p.s.i.Heretofore, it has frequently been necessary to extract amorphousfractions of the polymer in order to provide products having flexurablemoduli in this range. It is therefore highly desirable to minimize theproduction of amorphous polymer, as measured for example by the amountof polymer soluble in mixed xylenes.

It is thus an object of this invention to provide an improved processfor the production of olefin polymers.

Another object of this invention is to provide a polymerization processin which there is obtained an increase in flexural modulus and/or adecrease in the xylenes-soluble content of the polymer.

A further object of this invention is to provide a novel catalyst systemwhich when employed in a polymerization process results in an increaseof the ilexural modulus and/ or a decrease of xylenes-soluble content ofthe resulting polymer.

Other aspects, objects, andthe several advantages of this invention willbe apparent to those skilled in the art upon consideration of thisdisclosure.

According to this invention, I have discovered that polymers ofl-olefins (alpha olefins) can be obtained having increased flexuralmodulus values and/or decreased xylenes-soluble content when thepolymerization is conducted in the presence of an organometal modifiedcatalyst system. formed by admixing (a) an organoaluminum compound ormixture of compounds of the formula R AlX where in R is alkyl,cycloalkyl, aryl or combinations thereof having 1 to 12 carbon atoms, Xis a halogen and n is 1 or 2, (b) a titanium trichloride-aluminumtrichloride complex such as that resulting from the reaction of titaniumtetrachloride and aluminum and having the approximate formula TiCl/sAlCl and (c) a phosphorus compound selected from those of the formula(RO) P and (RO) PR, wherein R is alkyl, cycloalkyl, aryl or combinationsthereof having 1 to 12 carbon atoms, and R is selected from monoordihalosubstituted alkyl, cycloalkyl, and aryl groups and combinationsthereof having from 1 to 12 carbon atoms.

The enumeration of alkyl, cycloalkyl and aryl radicals herein indefining the formulas is intended to include the various mixed radicalssuch as alkaryl, aralkyl, alkylcycloalkyl, cycloalkylaryl, and the like.

The compounds and mixtures of compounds represented by the formulaR,,AlX and utilized as component (a) of the catalyst system of theinvention are well known in the art. Examples of such compounds arediethylaluminum chloride, ethylaluminum dichloride, ethylaluminumsesquichloride and the like.

The titanium chloride-aluminum chloride complex utilized as component(b) of the catalyst system according to this invention is also wellknown in the art. It can be formed, for example, by reacting titaniumtetrachloride with metallic aluminum. The complex can be represented bythe formula Ti'Cl A AlCl Examples of the phosphite adjuvants having theformula (R'O) P are tris (2-chlo ro ethyl )phosphite,

tris( 1,2-dichloroethyl phosphite,

tris 4-brom0phenyl) phosphite,

tris 3-iodocyclopentyl phosphite,

tris chloromethyl) pho sphite,

tris( 1,6-difluorohexyl) phosphite,

tris l-chloro-6 2-bromophenyl) hexyl] phosphite, tris[1-(2,4-dichloro-7ethylnaphthyl) ]phosphite, tris2bromo-4-methylcyclohexyl) phosphite,

tris 3iodo-S-phenylcyclopentyl) phosphite,

tris [2-( 3-chlorophenyl) cyclohexyl] phosphite, and the like.

Ratio to TiClsgAlch R A1X3- AdjuvanL Broad Preierre d 0.5:1-l0z1l:17.5:1 0.0l:1-1:1 0.05:l0.5:l

The total catalyst concentration is usually in the range 0.005 to 10weight percent of the olefin being polymerized, but concentrationsoutside this range are operative.

The polymerization reaction is carried out either in a mass systemi.e.,the olefin being polymerized acts as reaction mediumor in an inerthydrocarbon diluent, such as a paraflin, cycloparaflin, or aromatichydrocarbon or mixtures thereof having up to 20 carbon atoms permolecule. Examples of hydrocarbons that can be used are pentane, hexane,heptane, isooctane, eicosane, cyclohexane, methylcyclopentane, benzene,toluene, naphthalene, anthracene, and the like. When an inert diluent isused, the volume ratio of diluent to olefin is in the range of 1:1 to10:1, preferably 3:1 to 7:1.

The polymerization is conducted at temperatures in the range of 80 to250 F., preferably 100 to 200 F. The pressure can be suflicient tomaintain the reaction mixture substantially in liquid phase,orparticularly in a mass systemcan be such that the olefin is in the gasphase. The reaction time is in the range of 10 minutes to 75 hours, morefrequently 30 minutes to 25 hours.

Although the invention is illustrated by the polymerization ofpropylene, any aliphatic l-olefin having up to 8 carbon atoms permolecule can be used. Preferably those having 3 to 7 carbon atoms areused, such as propylene, l-butene, l-hexene, 4-methyl-1-pentene,l-heptene, and. the like. Copolymers of two or more of these olefins canbe prepared using the catalyst composition of this invention.

It is within the scope of the invention to use hydrogen in aconcentration of about 0. 08 to 1 mol percent of the propylene forcontrolling the molecular weight of the polymer.

The following example will further illustrate the invention, although itis not intended that the invention be limited thereto.

EXAMPLE Data illustrating the process of the invention were obtained bypolymerizing propylene in a one-liter, stirred reactor in 2.5-hour runsat 130 F. and about 300 p.s.i.g. with 250 grams of propylene and 1 literof hydrogen (equivalent to 0.67 mol percent hydrogen on the propylene)present in the reaction system.

The following results were obtained:

4 (RO)2PR wherein R is an alkyl, cycloalkyl, aryl or combinationsthereof having 1 to 12 carbon atoms, and R is selected from monoordihalo-substituted alkyl, cycloalkyl, and aryl groups and combinationsthereof having from 1 to 12 carbon atoms and wherein the ratio of thecompound (a) to the compound (b) is in the range of 0.5:1 to 10:1 andthe ratio of the compound (c) to the compound (b) is in the range of0.01:1 to 1:1.

2. A catalyst system according to claim 1 formed by admixing (a)diethylaluminum chloride, (b) titanium trichloride-aluminum trichloridecomplex, and (c) tris(2- chloroethyl) phosphite.

3. A catalyst system according to claim 1 formed by admixing (a)diethylaluminum chloride, (b) titanium trichloride-aluminum trichloridecomplex, and (c) octyldiphenyl phosphonite.

4. A catalyst system according to claim 1 formed by admixing (a)diethylaluminum chloride, (b) titanium trichloride-aluminum trichloridecomplex, and (c) triphenyl phosphonite.

5. A process which comprises polymerizing an aliphatic l-olefin havingfrom 3 to 8 carbon atoms per molecule in the presence of a catalystwhich forms on mixing (a) a compound of the formula R AlX wherein R isalkyl, cycloalkyl, aryl or combinations thereof having 1 to 12 carbonatoms, X is a halogen, and n is 1 or 2, (b) a titaniumtrichloride-aluminum trichloride complex having the approximate formulaTiCl /aAlCl and (c) a compound selected from those of the formulas(-R'O) P and wherein R is an alkyl, cycloalkyl, aryl, or combinationsthereof having 1 to 12 carbon atoms, and R is selected from monoordihalo-substituted alkyl, cycloalkyl and aryl groups and combinationsthereof having from 1 to 12 carbon atoms and wherein the ratio of thecompound (a) to the compound (b) is'in the range of 0.5:1 to 10:1 andthe ratio of the compound to the compound (b) is in the range of 0.01:1to 1:1.

6. A process according to claim wherein said catalyst is formed byadmixing (a) diethylaluminum chloride, (b)

Xylenes M01 13.1210 Catalyst, Productivity, Flexural soluble,

weight g./g. of Ti modulus, weight Melt RnAlXH-n Ad uVant TiCl AlOlpercent: complex p.s.i. x- B percent flow Adjuvant 2 0 1 0. 178 464 2075. 8 1. 14 None 2 0.10 1 0. 188 401 254 3. 5 3. 27 (ClCH2CH2O) P 2 0.201 0. 199 248 255 4. 6 1. 44 (ClCH2CHzO) P 3 0 1 0. 228 685 180 6. 5 0.70 None 3 0. 10 1 0. 240 689 195 5. 2 0. 58 CsHnP (0 Q1192 3 0. 1 0. 251667 191 4. 8 0. 32 O5H17P(OC H 3 0.30 1 0. 266 620 195 5. 6 0. 65CKH11P(OC H 3 0 1 0. 226 795 188 6. 6 1. 04 None 3 0. 10 1 0. 238 723202 5. 5 0. 67 CQH5P OO6H5)2 3 0.20 1 0. 250 661 211 4. 0 1.16 CaHP(OCaH5)z RnAlXZ-n was diethylaluminum chloride in all runs. Based onpropylene. .ASTM D 790-61.

Determined by placing 0.95 g. of polymer in a centrifuge tube, adding 95ml. mixed. xylenes, heating for 15 minutes at 285 F., cooling,centrifuging, evaporating the solvent from a ml. aliquot of thesupernatant llqllld, weighing the residue, and multiplying by 400.

"ASTM D 1238-621, Condition L.

The above data show that utilization of the catalyst titaniumtrichloride-aluminum trichloride complex, and

system of the invention results in a decrease in xylenessoluble contentand an increase in fiexural modulus of the polymer obtained therewith.

Reasonable variations and modifications of this invention can be made,or followed, in view of the foregoing disclosure, without departing fromthe spirit or scope thereof.

I claim:

1. A catalyst system formed on admixing (a) a compound of the formula RAlX wherein R is alkyl, cycloalkyl, aryl or combinations thereof having1 to 12 carbon atoms, X is a halogen, and n is 1 or 2, (b) a titaniumtrichloride-aluminum trichloride complex having the approximate formulaTiCl /3AlC1 and (c) a compound selected from those of the formulas (R'O)P and (c) tfis(2chloroethyl) phosphite.

7. A process according to claim 5 wherein said catalyst is formed byadmixing (a) diethylaluminum chloride, (b) titanium trichloride-aluminumtrichloride complex, and (c) octyldiphenyl phosphonite.

8. A process according to claim 5 wherein said catalyst is formed byadmixing (a) diethylaluminum chloride, (b) titanium trichloride-aluminumtrichloride complex, and (c) triphenyl phosphonite.

9. A process according to claim 5 wherein the polymerization is carriedout at a temperature in the range of to 250 F., at a pressure sufiicientto maintain the reaction mixture in the liquid phase.

10. A process according to claim 5 wherein said l-olefin is propyleneand hydrogen is present in a concentration of FOREIGN PATENTS about 0.0810 1 mol P61661111 of said olefin. 7 921 954 3/19 3 Great BritainReferences Cited JOSEPH L. SCHOFER, Primary Examiner UNITED STATESPATENTS 5 E. 1. SMITH, Assistant Examiner 3,040,014 6/1962 Lovett et a1.260-93.7 3,210,332 10/1955 Lyons et a1 250-93.7 118 3,414,554 12/1968Kahle et a1 260-93.7 252--429; 26() 83 2

